HYDROIDA. -BALE. 283 



SERTULARELLA TASMANICA, sp. nov. 

 (Plate xlvi., fig. 2.) 



Hydrocaulus about one inch in height (or more ?), stem 

 fascicled towards the base, branches irregularly pinnate, 

 springing from below the hydrothecse ; stem and branches 

 divided by oblique twisted joints into long internodes, each 

 bearing a hydrotheca close to the summit ; proximal inter- 

 nodes of the branches very long, smooth or slightly undu- 

 lated at their origin. 



Hydrotheca in a single plane, large, divergent, urceolate, 

 adnate for more than half their length ; border slightly 

 expanding, with four marginal teeth ; three strong internal 

 vertical teeth, two below the two upper emarginations of 

 the border and the third below the abcauline marginal tooth. 



Gonosome ? 



This species has the general habit of S. polyzonias and 

 S. gaudicliaudi, with the latter of which I was at first inclined 

 to place it. It is distinguished by the fasciculation of the 

 stem, which, however, did not extend far above the base. 

 The fascicle is formed, as Hartlaub points out in the case 

 of allied species, by the development of supplementary tubes 

 which originate at various points on the stem and grow 

 downward. The hydrothecse are larger than those of S. 

 gaudicJiaudi, their usual length being, between extreme 

 points, about .815mm., and they also differ from those of 

 that species in having a much larger proportion nearly 

 two-thirds of their length adnate. The border is of the 

 same form as that of S. polyzonias, and transverse to the 

 hydrotheca ; only rarely is there discernible a slight tendency 

 to the obliquity which, according to Billard, is a feature of 

 S. gaudichaudi. The internal vertical processes are large 

 and prominent. The portion of the internode below the 

 hydrotheca is very variable in length, about .450 mm. being 

 common ; the first internode of a branch, however, is much 

 longer, sometimes attaining as much as 1.8mm. between 

 its origin and the base of the first hydrotheca. These inter- 

 nodes may have a few faint undulations close to their origin, 

 but are more commonly quite smooth. 



Loc. Off South Cape, Tasmania, 75 fathoms. 



SERTULARELLA GAYI (Lamouroux). 



.Sertularia gayi, Lamouroux, Exp. Meth., 1821, p. 12, pi. 

 66, figs. 8-9. Id., Deslongchamps, Encyc. Meth., 

 Zooph., 1824, p. 682. Id., Milne -Edwards, Lamarck's 

 Anim. sans Vert., 2nd ed., ii., 1836, p. 152. 



